NIH Research Matters (December 16, 2013): Insights Into Brain Injury

New findings provide insight into the damage caused by mild traumatic brain injury and suggest approaches for reducing its harmful effects.

Nationwide, at least 1.7 million traumatic brain injuries occur each year, according to the U.S. Centers for Disease Control and Prevention. About 75% of these are concussions or other mild forms of traumatic brain injury.

Concussions are seldom life-threatening, but they can have serious and lasting effects. The specific damage that occurs in affected brain tissue is poorly understood. In their new study, researchers at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) examined the tissue and cellular responses in the brain after a concussion. Their findings appeared online in Nature on December 8, 2013.

NINDS scientist Dr. Lawrence Latour and his colleagues have been studying people who suffered a concussion but whose initial CT scans didn’t reveal physical damage to brain tissue. Using a contrast agent and MRI, they observed fluid leaking into the meninges, the outer covering of the brain, in 49% of 142 patients with concussion.

To more closely examine this type of injury, Dr. Dorian McGavern’s lab at NINDS developed a new, closed-skull model of brain trauma in mice. The model mirrors the effects seen in humans with mild traumatic brain injury. Laser scanning microscopy can safely be used in the mice to visualize brain tissue just beneath the skull surface.

The scientists initially saw cell death in the meninges and at the glial limitans (a thin barrier at the surface of the brain) in the mice. Cell death in the underlying brain tissue (the parenchyma) didn’t occur until 9-12 hours after injury.